Transmission of radiosignals employing undamped waves



1,556,740 R. a. WOOLVERTON TRANSHISSION OF RADIOSIGNALS- EMPLOYI NG UNDAHPED "Avis Original Filed July 25, 1921 Patented Oct. 13, 1925.

I UNITED- STATES PATENT OFFICE.

ROBERT B. WOOLVERTON, WASHINGTON, DISTRICT OF COLUMBIA,

TRANSMISSION OF 'RAIDIQSIGNALS EMPLOYING UNDAMPED WAVES.

- Original application filed July 25, 1921, Serial No. 487,247. Patent No. 1,504,462, dated August 12, 1924;

. Divided and this application filed December 10, 1923. SeriaINo. 679,850.

To all whom it may concern:

Be itknownthat- I, ROBERT B. VVOOLVER- TON, a citizenof the United'States, residing at'Washington, District of Columbia, have invented certain new and useful Improvements in Transmission of Radiosignals Employing Undamped Waves, of which the following is aspecification.

This, application is divisional from my copending application relating to transmission of radio signals employing undamped waves, Serial Number 487,24}, filed-July 25, 19-21, issued as Patent No. 1,504, 162, dated August 12, 1924; I

This invention relates to improvements in radio transmission apparatus wherein a gen erator of persistent or undamped oscillations, such as an arc generator, high frequency alternator or other source of energy is employed, and has for an object, the provision of transmitting apparatus of such arrangement as will permit of rapid fluctuations of the signal energy with the consequent production of sharp rapid signals at a receiving station, a result impossible to be obtained satisfactorily by use of heretofore prevalent apparatus.

Other objects will be in part obvious and in part pointed out hereinafter.

In the employment of generators such as the arc and high frequency alternator, the method heretofore employed has been to connect the source of persistent oscillations directly in the antenna circuit in order to make the over-all eiiiciency as high as pos sible. The interruptions in the antenna circuit were then produced by a variety of methods such as by varying the inductance in the antenna circuit by short-circuiting the turns, or by connecting across the generator an oscillatory circuit having a lower resistance than the antenna circuit, so that by closing this oscillatory or local tank circuit by means of a key, practically all of the generated radio frequency energy is diverted from the antenna circuit to the tank circuit. There are other means either employed or discarded, but all so far devised are unsatisfactory, because generally the factors, necessary to be varied to produce variations in the antenna current, have been too great, and tend therefore to prevent rapid transmission.

Because of the constant advance in receiving apparatus, less energy need now be generated in the antenna circuit tocover a given distance. Therefore, the'over-all efiiciency of a generator of radio frequencies 1s not paramount,this consideration giving ground to that of rapid transmission, a condition accomplished through the instrumentalities of my invention.

In order that the invention and its mode of application may be readily understood by persons skilled in the art, I have, in the ac companying illustrative drawings, and in the detailed following description based thereon, set forth severalflembodiments of the same. I V 1 In the draiwingsr Fig. 1 is a diagrammatic view fof'one form of a circuit provided with intelligence forming means, showing the resonance destroying means placed in the antenna circuit;

Fig. 2 is a diagrammatic view of a modification of that form ofmy invention shown in Fig. 1.

Instead of the arrangements shown in my copending application above referred to, it is to be also understood that instead of placing the resonance destroying means in the socalled oscillatory circuit, the same may be as advantageously arranged in the antenna. circuit of the apparatus as shown in the Figure 1. Herein the oscillatory circuit is identified at 5 and is coupled, inductively, at 6 to the antenna circuit 8 which latter circuit has the coils of a vari ometer 16 connected in series therein as at 18; an arm 17 extends from one of said coils and has the armature of a solenoid 10 connected thereto, whereby on the energization of the solenoid, the arm 17 will be caused to accordingly change the relative positioning of the coils of the variometer. An intelligence forming circuit 12*, corresponding to the circuits 12 and 12, is provided the solenoid 10, and obviously Will afford means for effecting the shifting of the arm 17.

7 From the foregoing, it is to be understood that With the change in the relative positioning of the several coils of the variometer, the inductance of the antenna circuit will be varied, and by consequence, resonanceas between the same and the oscillatory circuit will be destroyed. Thus, the forming of intelligence or signals by this intermittent destruction of resonance between the oscillatory and antenna circuits, is rendered possible.

In the Figure 2 I have disclosed another arrangement of means for destroying resonance between the oscillatory and antenna circuits, wherein the antenna circuit 8 has a. capacitance 19, arranged in the same, and about which asecond capacitance 9 is shunted. To the movable element of the capacitance 9, the armature of the solenoid 10 is connected, being insulated there from as at 11. The terminals of the solenoid 10 are connected to the opposite sides. of an intelligence forming circuit 12 cor responding to the circuit 12 and therefore, with closing of the key in said circuit, the solenoid 10 Will be energized, thus varying the positioning of the movable element of the capacitance 9 with relation to the fixed element thereof whereby to vary or change the capacitance of the antenna circuit 8 and consequently destroy resonance as between said antenna circuit and the oscillatory circuit in order that the forming of intelligence or signals may be practically effected.

Manifestly, the arrangements shown throughout are capable of considerable modification, and such modification as is within the scope of my claim, I consider within the spirit of my invention.

I claim In radio transmitting apparatus for undamped waves, an intelligence forming circuit including a solenoid, a tuned oscillatorycircuit, shunted about the generator of said transmitting apparatus, an antenna circuit inductively coupled to the tuned 0scillatory circuit, said circuits being in exact resonance, a variable I inductance connected in series in the antenna circuit, an armfor connecting said variable inductance with said solenoid, and means for varying the relative positioning of the elements of said variable inductance for the purpose of energizing said solenoid and destroying the exact resonance between said oscillatory and antenna circuits, and thereby forming signals in said intelligence circuit;

In testimony whereof I aflix my signature.

ROBERT B. WOOLVERT O-N. 

